Radio apparatus



July 2, 1929. A. A. KENT 1.719.014

RADIO APPARATUS Filed July 21 1922 3 Sheets-Sheet 1 Juiy' 2, 1929.

Juiy 2, 929. A. A. KENT 1.719.014

RADIO APPARATUS Filed July 21, 1922 3 Sheets-Sheet 5 I 1 t 6' '1 l2! K 17 1 9 10 0 7 7 4! 12 44 16 4 4 17 7 J 41 J! Z Patented July 2, 1929.

ARTHUR ATWATEB KENT, ARDMORE, PENNSYLVANIA.

RADIO APPARATUS.

Application filed July 21,

My invention relates to apparatus utilizablc more particularly in radio telephony or telegraphy, but utilizable. also for amplifying, or detecting andamplifying, electrical cll'ccts, in general, and comprising thermionic devices or vacuum tubes of the audion type, or

equivalent, and means for correlating or coupling them.

In one of its aspects, my invention comprises a unit consisting of a plurality of thermionic devices mounted upon a wall 01' cover of a casing, with' associated parts mounted upon the interior of the wall or casing, and appurtenant apparatus, as conpling means. disposed within the casing.

llly-invention resides also in a unit for coupling thermionic devices and comprising an impedance or inductive reactance and a condenser. 3 I

My invention resides also in a disposition of impedanccs or inductively reactive coupling devices placed adjacent each other and so disposed, wound or connected that undesired oscillations. particularly those of audio frequency causing howling, will be prevented.

My invention resides in further features of structure, combination and arrangement hereinafter described and claimed.

. For an illustration of one of various forms my invention may take, reference is to be had to the accompanying drawings, in which: I

Figs. 1 and 2 are side elevational and top plan views, respectively, of apparatus embodying my invention.

Fig. 3 is a plan view of the under side of the casing cover showing the coupling units therein in section.

Fig. 4 is a horizontal sectional view, partly in plan. I V I Fig. 5 is a vertical sectional view of the apparatus. I

Fig. 6 is a diagrammatic view of a circuit arrangement.

Fig. 7 is a fragmentary diagrannnatlic view explanatory of the relation of the coupling devices.

Referring to the drawing, 1 is a base of sheet metal having formed therein the annular upstanding rib 2 within which is received and secured, as by welding or otherwise, the cup-shaped casing 3, which may be provided with the bottom 4.

Forming a wall orclosure for the casing -1922.-' Serial mi. $6,423.

3 is the cover 6 having the integral flange 9 is adapted to receive the terminal end of a thermionic device or vacuum tube, as an audlon, or equivalent, and comprising, as -well understood in the art, a filament cathode, an anode, and a control electrode, the latter generally a grid disposed between the anode and cathode. The sleeve or base of the vacuum tube carries a pin, which is adapted to engage in the bayonet slot 11 in the sleeve or socket member 8 or 9 for holdmg the vacuum tube in position. At the base of the vacuum tube are provided two terminals for the filament, a terminal for the grid, and a terminal for the anode or plate, these terminals engaging and electrically contacting with the spring or resilient sheet metal terminals disposed on the underside of the cover 6 in association with each of the socket members 8 and 9. With the socket 8 are associated the filament terminal springs or contacts 12 and 13, grid spring or contact 14, and anode spring or contact 15, the ends of these contacts being disposed beneath the openings 16 in the cover 6. The contacts on the base of the audion project through the 0 ning 16, the filament terminals on ging t e contacts 12 and 13, the grid terminal engaging the contact 14, and the anode terminal engaging the contact 15. These contacts are secured to the under side of the cover- 6 by any suitable means, as, for example, the screws 17 extending upwardly throu h the cover 6 and secured by the nut mem rs 17".

For the vacuum tube received in the socket 9ther'e are similarly provided on the under side of the cover 6 the filament springs or contacts 18 and 19, the grid spring or contact 20 and the anode or plate contact or spring 21, secured to the cover 6 by any suitable means, as screws and nuts 17 and .17. The yielding ends of these contacts are disposed beneath the circular aperture 22 in the cover 6, and through the'aperture extend the terminals on the end .of the-vacuum tube, the filament terminals engaging the contacts 18 and '19, the anodeterminal engaging the contact 21, and the-grid terminal engaging the contact 20.

Supported upon the under side of the cover 6 are grid leak resistance members '23 and 24 constituting high resistances connccted, respectively, between the aforesaid contacts 12 and 14, and contact-s18 and 2t).

Carried on the underside of the cover 6 is 'the filament rheostat comprising a resistance wire wrapped around the Hat strip member 26 of insulating material, and secured flatwise by screws 27 to the cover 6.

-The filament contacts 13 and 18 are conconnections to externally nected togetherand to the rotatable contact 28, movable acrossthe resistance wire 25 by the handle or knob 29 on the outside of the cover (Shaving the position indicating member 29 and attached to ,the contact 'lever 28 by the shaft 30 extending through cover 6., p

Carried by the cover 6 are the binding posts'31 to 36 inclusive for facilitating the employed telephoneor otherreceiving mstrument '1, Fig.

" 6, anode or plate circuit battery B, filament battery A, and thermionic device, audion or vacuum tube V and its connections.

lVithin the casing 3 are disposed the impedances or inductive reactances I and I for efi'eeting'couplings of the character hereinafter described. These lmpedances may audio frequency impedance, according to circumstances ordesire. As illustrated, each of the impedances I, I com rises a coil- 37, of fine wire of great num er of turns, disposed upon an insulating sleeve 38, Figs. 4 and 5, within which is disposed the magnetizable core 39, consisting of a bundle of fine iron wires. Forming units with the impedances I and I are the condensers K and K, which may be of any suitable type. In the example illustrated, eachof' the condensers' is of the so-called rolled type, comprising alternating strips of insulating material and tin foil rolled into a unit. Each condenser unit is disposed upon its associated impedance or coupling unit, and is suitably bound thereto, as by binding member 40.

The-im edancecondenserunits are suitably positioned within the casing C, as hereinafter described, and are preferably held in place and shielded against access of from the condenser C to the moisture by the insulating material; 41,

which is poured in the fluid state and'then congeals or hardens,.such insulating ma-' terial being wax, asphaltic material or 4 14, while the'other terminal of the condenser K is connected to the outer terminal of the impedance I, and these two terminals connect by conductor 43 with the binding post 31, the other terminal of the impedance I connecting by conductor 44 with thebinding post 32.

Similarly, one terminal of the condenser K connects by conductor 45 with the grid contact 20, while the other terminal of the condenser K connects to the outer terminal of the winding of the impedance. I, and these last two terminals are connected by conductor-A6 with the anode contact 1.); and the inner teri'ninal of' the winding of the ii'npedance I connects by conductor 47 with the binding post 35.

Within the apparatus the filament contacts 12 and 19 are connected to each other, and by conductor 48 are connected to the binding post 3al while one end of the rheostat winding 25 is connected by conductor 49 with binding post 33. The plate contact 21 is connected by conductor 50 with the binding post 36.

Referring to Fig. 6, the aforesaid connect-lens appear, and in addition, connections Wll-ll external devices. V represents an audion or thermionic vacuum tube having the filament 7, grid 7 and plate or anode. (1.. The filament f is supplied by currenttrmn the aforesaid battery A, which also supplies current to the filaments of the vacuum tubesplaced in the sockets 8 and 9, the rheostat 25 being in series with and simultaneously varying the current in the filaments of the vacuum tubes placed in the sockets 8 and 9. The strength of the current through the filament f of the tube V is independently varied by the rheostat 51.

L is the secondary of an oscillation transformer whose primary may be traversed by the received oscillations, as in an antenna circuit or path. Shunting the inductance Lisa the variable condenser C for tuning the secondary circuit to the frequency of the received oscillations. Connection is made grid 9 through the condenser C shunted by a high resistance 52. The anode a is connected through the tickler coil or oscillation transformer winding 53, if and when regenerative action is required, as well understood in the art. The anode circuit continues to the binding post 31 and thence through the impedance.

and the entire orany suitable portion of the battery B, in the example illustrated,

one-half of the battery B being employed.

The plate circuit returns through the bat tery B to the binding post 34, and thence by conductor 54 to one terminal of the lilament f, which filament is also. connected to the other terminal of the condenser C. A condenser C may also be employed between the filament f and the connection to the anode a.

The impedance I is in the anode circuit comprising the anode terminal 15 of the vacuum tube received in the socket 8. In circuit with the impedance I is the entire battery B. The grid of the vacuum who received in the socket 8 is connected through the condenser K with one terminal of the impedance I, and the filament of the same vacuum tube is connected through a portion of the battery B to the other terminal of the impedance I. The grid of the vacuum tube received in the socket 9 is connected through the condenser K with one terminal of the impedance I, and the filament of the same vacuum tube is connected through the entire battery 13 with the other terminal of the inductance I. The telephone Tor similar instrmnent or device is connected to the binding posts 35 and 36, and thereby in-' eluded in the plate or anode circuit of the vacuum tube received in the socket 9, and in series with such anode circuit is the entire battery B.

Utilizing the vacuum tube V as a detector for radio telephonic or telegraphic messages or signals, there is produced across the terminals of the impedance I a potential var ing in accord with the message or signal. This potential is impressed upon the. grid circuit of the vacuum tube received-in the socket 8, with the result that in the plate circuit of such vacuum tube there are produced corresponding variations, eifecting' corresponding variations of potential d1f-' fcrence between the terminals of the impedance I. These potential differences are impressed upon the grid circuit of the vacuum tube received in the socket 9, and there is accordingly produced corresponding varia--- tions of current in the plate circuit ther'eof, including the telephone or other instrument T.

The arrangement in the example illustratcd comprises, therefore, a detector'V and two stages of audio frequency amplification, the apparatus unit itself being a two-stage amplifier with coupling impedances.

The impedances I and I are necessarily more or less close to each other when assembled in a unit, as in a casing 3, as illustrated. If the current in the anode circuit of the detectonV is zero or of small magnitude, as when there is no or only small current through the filament f, there is no or only slight current flowing from battery B through the impedance I. In such case there will be produced by the amlifier tubes and their circuits local oscilations, particularly of audio frequency, causing howling, unless the impedances I and I, which are wound in similar directions and in general, similarly constrlu-ted, are revcrsedin their positions with respect to each other, as indicated in Figs. 4 and (3; or unless theimpcdances have their windings in such directions.relatively to each other or connected relative] y to each other that the same effect is produced as by the aforesaid reversal of position. When the anode circuit current through the impedance I is small or zero, the'impedance I, when adjacent to the impedance I, operates as the primary of a transformer inductivcl y afl'ectmg the impedance I, which may then be considered the secondary of a transformer which, except for the aforesaid precaution, will impress upon the grid of the first ainplitiertube, received in the socket 8, clci:t|'u-' motive-force of such direction as to cause such change in the current invthe anode circuit through the impedance 1 as to set up audio frequency oscillations.

3y reversing the positions of similarly wound and constructed impedances, as indicated in Figs. 4 and 6, and with anode circuit currents flowing through both, the relation for preventing howling when the anode circuit current in one of them, as I, g is zero or of small value, 'is such, as regards the polarity of the cores 39, that, as indi'cated in Fig. 7, similar ends of the cores are of different polarities, as indicated by The casing member 3 and the bottom 1 may be of iron or steel or other magnetizable material, and ct, by observing the precautions aforesait no howling or audio fro-- quency oscillations will be produced.

It is preferredthat the cores 39 of the impedances be simple straight cores, as illustrated, though it will be understood that my invention is not limited in this regard and that difierently disposed or shaped or arranged cores may be employed.

With core structures as illustrated, the

magnetic circuit of each impedance is open in the sense thata substantial portion thereof is in air or medium other than magnetizablc material, though where the bottom 1 or the casing 3 is of magnetizable material the magnetic circuits are in part through those members, particularly as regards low frequency or zero frequency currents through the impedance windings.

By the employment ofimpedances as described, conducting or metallic shield structure to prevent oscillations or howling is not require By way of example, but without limitation of my invention thereto, each of the condensers K and K may have a capacity of the order of one-tenth of a mic'rofarad; and each of the impedanees I, I may consist of acoil having a number 0 turns of the order of 15,000 or 20,000 turns or convolutions, of No.

38 Brown & Sharp gauge insulated 00 persenses and to substantially like extents, such adjustments of the filament currents serving to vary theloudness of the speech or signals heard inthe telephone T.

\Vhen impedances, as I, I are employed as herein deseribed'within the range of influence upon each other as regards production of oscillations, as audio frequency oscillations, theirefli'ects upon each other in this respect may be reduced or eliminated by enclosing one or both of them within a closed or the tube given a or substantiallyclosed magnetic shell; for

. example, each of the impedances may be disposed within an iron tube, the tube being closed at its endsby magnetizablo material, length considerably greater than the length of the impedance structure, it being understood, ho'\vever, that the extra length of tube or the end closures are not in all cases or under all circumstances essential.

It shall be understood that my invention is not limited to the employment of impedances, as I, I, but that in lieu of them may be used transformers, having primary and secondary windings, utilized for coupling the anode circuit of one audion to the grid circuit of the next, such transformers being either of the radio or audio frequency types, or some of them may be of radio and the remainder of audio frequency types. And when transformers. are so employed, they .may be so placed or disposed as are the imiedances 1,1 and are-prefe ably embedded in insulating material in the casing 3.

For brevity, the term audion is employed in the appended claims in the generic sense to include thermionic devices comprising an anode, cathode and a control electrode as a grid or equivalent.

What I claim is:

1. An audion unit comprising a casing, a cover therefor, a socket carried by said cover upon the exterior thereof, contacts carried upon the inside of said cover and adapted to engage electrodes of an audion received insaid socket, audion coupling means disposed in said casing, insulating material congealed in said casing and holding said coupling means m position therein,

said contacts disposed in a free space be- 7 tween said insulating material and cover,

and conductors extendin from said couling means through said insulating material into said free space for connecting said coupling means in eircu1 2. An audion umt comprising a casing, a cover therefor, a. socket carried by said cover upon the exterior thereof, contacts carried upon the inside-of said cover and adapted to engage lelectrodes'ot an audion received in said socket,-insulating material in said casing, a grid leak disposed within said casing and carried by said cover in the space between said insulating material and said cover, and audion coupling means embedded in said insulating material and supported independently of: said cover" An audion unit comprising a casing, a cover therefor, a socket carried by said cover upon the exterior thereof, contacts carried upon the inside of said cover and adapted to engage electrodes of an audion received in said socket, insulating material 1n said casing, a filament circuit rheostat 'arried by said cover in the space between said insulating material and said cover, means on the exterior of said cover for actuating said rheostat, and audion coupling means embedded in said insulating material and supported independently of said cover.

4;. An audion unit compr'isinga casing, a

cover therefor, a plurality of audion sockets carried by-said cover on the exterior thereof, a plurality of audion coupling means, in sulating material in said casing in which said coupling means are embedded and thereby held in predetermined position with respect to each other, and contacts associated with said sockets and disposed in the space between said cover and said insulating material.

5. An audion unit comprising a casing of magnctizable material, a cover therefor, a plurality of audion sockets carried by said cover, a plurality of audion coupling means,

and insulating material in said casing embedding said coupling means and holding them in predetermined position with respect to each other and to said casing.

6. An audion unit comprising a casing, a cover therefor, a plurality of audion sockets carried by said cover, insulating material in said casing, a plurality of audion coupling means embedded in said insulating material, and held thereby in position with respect to each other preventing substantial coupling between them.

7. An audion unit comprising a. casing, a cover therefor, a plurality of audion sockets carried by said cover, insulating material in said casing, a plurality of audion coupling means embedded in said insulating material, said coupling means being held by said insulating material with their axes substantially parallel, and connections to 130 said coupling means so related to each other that the coupling between said coupling means is substantially zero.

8. An audion unit comprising a magnetizalile casing, a cover therefor, a plurality of audion sockets carried by said cover, insulating material in said casing, a plurality of coupling means embedded in said casing and held in predetermined position with respect to each by said insulating material, each of said coupling means comprising a magnetizable core and a winding thereon, said cores disposed substantially pa 'allel with an adjacent wall of said casing, and substantially parallel with each other, and connections to said coupling means so related to each other than the coupling between said coupling means is substantially zero.

9. An audion unit comprising a casing, a cover therefor, :uidion-holding means carried by said cover, a plurality of audion conplingiueans in said casing each comprising a winding, the axes of said wnuliugs disposed substantially parallel to each other, and connection'to said coupling means to efi'ect a polarity relation between said coupling means to prevent production of local oscillations.

10. An audion unit comprising a magnetizable casing, a cover therefor, audionholding means carried by said cover, a plurality of audion coupling means In said casing, each comprising a wmdmg, the axes of said windings disposed substantially parallel to each other, and connections to said coupling means to effect a polarity relationbetween said coupling means to prevent production of local oscillations.

11. A coupling unit for cascaded audions comprising a plurality of coupling inductances having magnetizable cores, a magnetizable member adjacent which said cores are disposed in substantially parallel relation to each other and closely spaced, said inductances being disposed respectively in the anode circuits of neighboring audions, said inductances being so related to each other that their magnetic fluxes are incapable of causing local oscillations in the presence of said magnetizable member.

12. A coupling unit for cascaded audions comprising a casing having a wall of magnetizable material, a. plurality of audion coupling means in said casing, each of said coupling means comprising a winding, a portion of said wall being within the region of influence of the magnetic fields produced by said windings, each of said means coupling the output circuit of one audion with the input circuit of another, said windings disposed substantially parallel to each other in close relation, and so related to each other that the mutual magnetic coupling is of a character to prevent local oscillations.

13. An audion coupling unit, comprising an enclosing casing having external terminals thereon adapted to be connected to elements of a radio receiving circuit, a plurality of choke coils within said. casing, electrically connected to said terminals, a magnetic circuit for said coils comprising an internal core structure upon which each coil is mounted in side by side relation, said circuit having portions which magnetically couple said cores in mutual flux relation, and another portion which shunts a portion of said mutual flux.

14. An audion coupling unit comprising an enclosing casing, insulating material in said casing, a plurality of audion coupling means embedded in said material and held thereby in predetermined position with respect to each other and to said casing, whereby substantial coupling between said means is prevented.

1,5. An audion coupling unit comprising a casing of metallic material and a cover of insulation material having a plurality of external terminals thereon, insulating material in said casing, a plurality-of audion coupling means connected to said terminals and embedded in said material, and held thereby in predetermined position with re spect to each other and to said casin 16. An audion coupling unit for cascaded thermionic amplifiers comprising coils having iron cores adapted to be connected in the circuits of succeeding audions, and in lixed special relation so that there is a mag netic flux coupling said coils, said coils being relatively so connected that the mutual magnetic flux is in such direction to oppose the generation of oscillations.

In testimony whereof I have hereunto afmy signature this 20th day of July,

ARTHUR ATWATER KENT.

Patent No. 1,719, 014.

cen'rmca'm or comcTroN. p

Granted July [929; to ARTHUR ATWATER KENT. 7

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction; as follows: Page 3, line 22, for I "I" read "I page 5, line 99, claim 16, for the word "special" read "spacial"; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 24th day of June, A. D. 1930.

a M. J. Moore, (Seal) Acting C-omniissioner of Patents.

CERTIFICATE OF CORRECTION.

Patent No. 1,719,014. Granted July 2, 1929, to

ARTHUR ATWATER KENT.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 3, line 22, for "I" read"l page 5, line 99, claim 16, for the word "special" read "spacial"; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 24th day of June, A. D. 1930.

M. J. Moore, (Seal) Acting Qommissioner of Patents. 

